Structural Dynamics of Presynaptic Membrane Fusion

项目描述（由申请人提供）：本项目由三个项目和三个核心组成，旨在阐明突触前胞吐中膜融合的分子机制。这个过程的核心分子机器是SNARE复合体，它在突触前膜融合过程中由其组成部分组装而成。来自SNARE复合物折叠和组装的能量驱动囊泡和细胞膜双层的动力学阻断融合。包括突触结合蛋白、复合蛋白和Munc 18在内的调节蛋白使SNARE复合物的形成和融合对钙敏感，并通过在结构机制水平上仍然知之甚少的机制控制SNARE组装和融合。一群才华横溢的生物化学家，结构生物学家，生物化学家和细胞生物学家已经聚集在这个项目中，共同解决突触前膜融合的几个关键问题。SNARE组装和融合中间体将在结构和功能上的特点和相关性; SNARE组装的辅助蛋白和其耦合融合的调节的结构和生物物理基础将被阐明;和新生和成熟融合孔的超分子结构的演变将被检查。这些方法的范围从高分辨率分子光谱学和结构生物学到生物化学，分子和生物学解剖过程与明智选择的突变体，先进的光学和细胞生物学方法。 公共卫生相关性：突触囊泡与神经元细胞膜的融合是突触传递的关键要素。突触传递的缺陷会导致癫痫、抑郁和其他神经系统疾病。了解突触处膜融合的分子机制和结构基础将最终有助于对抗这些疾病。

DESCRIPTION (provided by applicant): This program project consisting of three projects and three cores aims at elucidating molecular mechanisms that are responsible for membrane fusion in presynaptic exocytosis. The molecular machine at the center of this process is the SNARE complex that assembles from its components during presynaptic membrane fusion. Energy derived from SNARE complex folding and assembly drives the kinetically blocked fusion of vesicle and cell membrane bilayers. Regulatory proteins including synaptotagmin, complexin, and Munc18 render SNARE complex formation and fusion sensitive to calcium and control SNARE assembly and fusion by mechanisms that are still poorly understood at the structural mechanistic level. A group of talented biochemists, structural biologists, biophysicists, and cell biologists has been assembled in this program project to jointly tackle several key questions of presynaptic membrane fusion. SNARE assembly and fusion intermediates will be structurally and functionally characterized and correlated; the structural and biophysical basis of the regulation of SNARE assembly by accessory proteins and its coupling to fusion will be elucidated; and the evolution of the supramolecular architecture of nascent and mature fusion pores will be examined. The approaches range from high-resolution molecular spectroscopy and structural biology to biochemical and molecular and biological dissections of the process with judiciously selected mutants, to advanced optical and cell biological methods. PUBLIC HEALTH RELEVANCE: Fusion of synaptic vesicles with the cell membranes of neurons is a key element of synaptic transmission. Defects in synaptic transmission lead to epilepsy, depression, and other neurological disorders. Understanding the molecular mechanism and structural basis of membrane fusion at the synapse will ultimately help to combat these diseases.